- Timestamp:
- 08/12/2008 10:04:34 PM (4 months ago)
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dotorg/trunk/html/beps/bep_0022.html (modified) (4 diffs)
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dotorg/trunk/html/beps/bep_0022.html
r11131 r11133 39 39 <tr class="field"><th class="field-name">Title:</th><td class="field-body">BitTorrent Local Tracker Discovery Protocol</td> 40 40 </tr> 41 <tr class="field"><th class="field-name">Version:</th><td class="field-body">111 29</td>42 </tr> 43 <tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference external" href="http://bittorrent.org/trac/browser/dotorg/trunk/html/beps/bep_0022.rst">2008-08-12 2 1:23:42-0700 (Tue, 12 Aug 2008)</a></td>41 <tr class="field"><th class="field-name">Version:</th><td class="field-body">11132</td> 42 </tr> 43 <tr class="field"><th class="field-name">Last-Modified:</th><td class="field-body"><a class="reference external" href="http://bittorrent.org/trac/browser/dotorg/trunk/html/beps/bep_0022.rst">2008-08-12 22:03:39 -0700 (Tue, 12 Aug 2008)</a></td> 44 44 </tr> 45 45 <tr class="field"><th class="field-name">Author:</th><td class="field-body">David Harrison <dave at bittorrent.com>, Stanislav Shalunov <shalunov at bittorrent.com>, Greg Hazel <greg at bittorrent.com></td> … … 140 140 <p>The domain name returned from the reverse DNS lookup is specific to 141 141 the querying host. In the naive implementation in DNS, there would be 142 one SRV resource record for every querying host. A natural but 143 incorrect solution is to use a wildcard of the form:</p> 142 one SRV resource record for every querying host. This would work but 143 is burdensome. A natural, seemingly less burdensome, but incorrect 144 solution is to use a wildcard of the form:</p> 144 145 <pre class="literal-block"> 145 146 *.pacbell.net … … 147 148 <p>If wildcards are implemented according to the algorithm in section 148 149 4.3.2 in <a class="footnote-reference" href="#rfc-1034" id="id5">[4]</a> then all subdomains of pacbell.net that do not 149 have an exact label match will match the wildcard. Thus,</p> 150 have an exact label match will match the wildcard. Thus unless there 151 is an exact match then queries for</p> 152 <pre class="literal-block"> 153 _bittorrent-tracker._tcp.adsl-69-107-0-14.dsl.pltn13.pacbell.net 154 </pre> 155 <p>and</p> 150 156 <pre class="literal-block"> 151 157 _jabber._tcp.pacbell.net 152 </pre>153 <p>and</p>154 <pre class="literal-block">155 _bittorrent-tracker._tcp.pacbell.net156 158 </pre> 157 159 <p>both match *.pacbell.net and all SRV resource records with owner … … 165 167 _bittorrent-tracker._tcp.*.pacbell.net 166 168 </pre> 167 <p> However, section 4.3.3 in <a class="footnote-reference" href="#rfc-1034" id="id6">[4]</a> specifies that wildcards only168 appear as the first label in a domain name. This restriction was 169 lifted in <a class="footnote-reference" href="#rfc-4592" id="id7">[7]</a>, but not with semantics applicable to our use 170 case. An asterisk not at the beginning of a domain name is not 171 treated like awildcard. Only a lookup for the exact domain name</p>169 <p>Section 4.3.3 in <a class="footnote-reference" href="#rfc-1034" id="id6">[4]</a> specifies that wildcards only appear as 170 the first label in a domain name. This restriction was lifted in 171 <a class="footnote-reference" href="#rfc-4592" id="id7">[7]</a>, but not with semantics applicable to our use case. An 172 asterisk not at the beginning of a domain name is not treated like a 173 wildcard. Only a lookup for the exact domain name</p> 172 174 <pre class="literal-block"> 173 175 _bittorrent-tracker._tcp.*.pacbell.net